Threaded Muffler Falling off

[Scooter99]

Greetings,

I have an old T-Force riding mower with a Craftsman engine. It runs great but just as I was finishing up mowing the lawn today, the muffler fell off.

It's a threaded straight pipe with the muffler on the end. I let the mower cool for a few minutes and screwed the muffler back into engine. Unfortunetaly, after a couple of rounds, it fell off again. I screwed it in again and managed to complete my mowing just before it fell off for the 3rd time.

The threads seemed OK. When I re-attached the muffler, I made sure it was tight as I could get it, but that doesn't appear to be good enough.

I was wondering if I'm doing something wrong or is there a trick that I'm missing to keep the muffler on. I have very little money so a costy repair or new mower is not an option.

Thanks so much for any directions or suggestions that might help me solve this problem.

 

[motoman]

Can you take a picture up close of the threaded straight pipe and send it to us?

 

[reynoldston]

I know the muffler you are talking about. They were on a lot of the older mowers and I have seen them as a cheap replacement muffler. What you are going to need is a lock nut. Its the same thread as electrical pipe conduit uses so you should be able to buy a lock nut from a electrical store.

 

[hitmanharleyk]

I know the muffler you are talking about. They were on a lot of the older mowers and I have seen them as a cheap replacement muffler. What you are going to need is a lock nut. Its the same thread as electrical pipe conduit uses so you should be able to buy a lock nut from a electrical store.

The item looks like the one in the below link.

Shop Gampak 1" Rigid Nut at Lowes.com

 

[Scooter99]

Thanks so much for the information. You guys were right on target.

I cut off the old locknut and purchased a new one from Lowes. I screwed the new one over the threaded end of the muffler and tightened the mufler as tight as I could to the engine block. I had to remove the front grill panel on the T-Force to get my pliers around the lock nut so I could lock it tight against the engine. I was concerned that there were not enough threads left in the engine block but luckily, there were.

I can report that I spent 1.5 hours mowing the lawn and the muffler didn't budge. Total cost of repair was 70 cents.

Thanks again and keep on mowin' :biggrin:

 

[hitmanharleyk]

Next time you can use a flat head screw driver and a hammer to tighten or loosen the lock nut, just place the tip of the screw driver on one of the "ears" of the lock nut and bump it with the hammer.